During transmission of an IP data packet in a wireless communication field, the IP data packet is usually compressed to achieve a purpose of saving an air interface resource. In the prior art, a header compression manner is used as a compression manner for an IP data packet, that is, an IP header of the IP data packet is compressed. Header compression is mainly aimed at an IP data packet in which the data amount of an IP header is large but the data amount of IP data is small. Usually, IP headers of multiple such IP data packets do not change greatly and repetition is high. The IP header of the IP data packet is compressed by using a header compression method, which may achieve the purpose of saving an air interface resource.
In actual application, services such as Web browse and email services are widely used by wireless users. Header compression is not applicable to this part of data, but a burden of air interface transmission is increased if this part of data is transmitted on an air interface without being compressed.